10.2.2 Raised ICP Consequences and Management

Question 1

Why is recognising raised ICP so important?

Answer 1

Early recognition and treatment reduces risk of:
- Irreversible brain damage or death
- Inappropriate management e.g. lumbar puncture

Question 2

What can a lumbar puncture cause?

Answer 2

In increased ICP an LP can cause acute pressure gradient which can cause the brain to hearniate

Question 3

What imaging can be used to provide additional evidence of raised ICP?

Answer 3

CT

Question 4

What are the common presenting features of raised ICP

Answer 4

Headache- constant, worse in the morning

Vomiting

Visual disturbances
- Impaired visual acuity (may be transient)
- Papilloedema
- Diplopia (CNVI, compressed with raised ICP due to its vertical course)

Question 5

If ICP continues to rise what presenting features will there be?

Answer 5

Difficulty concentrating

Reduced GCS
- Confusion
- Drowsiness
- Unconscious

Focal neurological signs

Seizures

Increased BP

Question 6

What are the radiological features of rasied ICP?

Answer 6

Midlife shift- indicates subfalcine herniation

Effacement of ventricles (&other CSF spaces)

Loss of grey-white matter differentiation

Question 7

What are the different types of herniation in raised ICP?

Answer 7

Subfalcine
- Cingulate gyrus under falx cerebri ACA is vulnerable as it’s midline

Transtentorial (uncal)
- CNIII is vulnerable, compression of cerebellar peduncle

Tonsillar (coning)
- Cerebellar tonsils herniate through foramen magnum
- Compression of brainstem, final stages- usually terminal

Central downward
- Medial temporal lobe or other midline strucutres herniate through tentoial notch

External
- Through skull fracture or craniotomy

Question 8

What are the late features of raised ICP?

Answer 8

Brain herniation

Cushing’s Triad
- High Blood pressure: attempting to maintain CPP, in face of high ICP
- Bradycardia: BP detected by baroreceptors, increases vagal tone (may be due to compression on brainstem)
- Irregular breathing: compression on cardio-respiratory centres in medulla

Question 9

How are patients with acutely raised ICP managed?

Answer 9

Resuscitate and stabilise patient- ABC before D

Recognise raised ICP early and possible cause
-History and clinical examination findings
-Imaging (CT)

Begin measures to prevent worsening of increased ICP and secondary brain injury from ischaemia and compression

Consult/refer to neurosurgeons

Question 10

What brain protection measures can be taken?

Answer 10

Elevate head of bed 10-15 degrees
- Maximal cerebral venous drainage to heart

Adequate oxygenation - avoid hypo/hyperventilation
- Maximises O2 delivery to brain
- Prevents cerebral vasoconstriction

Maintain normal BP
- Avoid hypotension to ensure adequate CPP,
- If BP high do not try to lower - this is allowing CPP to be maintained, lowering can causebrain hypoxia

Decreased cerebral metabolic rate
- Decreases demands for O2 of brain
- Sedate, analgesia, paralysis, avoid hyperthermia, treat seizures

Question 11

What is the ongoing management of raised ICP?

Answer 11

Hypertonic saline or mannitol

Regularly re-evaulate and monitor neuro-observations

May need invasive monitoring of ICP e.g. placement of bolt or external ventricular drain to provide continuous monitoring

Aim to maintain ICP < 20-25 mmHg